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Saturday, June 06, 2009

Rajeev Motwani, R.I.P

Rajeev Motwani passed away unexpectedly yesterday. He will be remembered for many things: his influence on the creation of Google, the foundational randomized algorithms book that he wrote with Prabhakar Raghavan, his role in the PCP theorem, and his extensive presence in the Bay Area investor community. Within the theory community, he will also be remembered by the legion of students he trained, including your humble blogger. Update: Ashish Goel @ Stanford has a page where you can also post comments.

The influence an advisor has on their students can be subtle: as a grad student, I spent much of my time resisting, pushing back, trying to find my own voice. But more and more, as I look back, I see how he influenced my taste in problems and the sensibility I bring to my work.

He had incredible breadth to go along with his depth. I remember scouring his web page in the early years of grad school, and seeing papers in robotics, databases, compilers, parallel systems, as well as in algorithms. Having spent time working in more applied areas, I can appreciate now how difficult it must have been to do that, and have the kinds of impact he had. That kind of incisiveness, that could cut to the heart of a modelling problem, was a hallmark of his more "applied" work.

There's something special that comes with the ability to have a great career and train so many students. There are many famous researchers in the field who do one or the other, and Rajeev had a knack of catalysing the best from his students, and helping them succeed no matter what area they happened to work in. To this day, I'll catch myself thinking, "what did Rajeev do in this situation" when I'm interacting with my own students.

As an advisor, the best way to describe him was 'laid-back'. He wasn't the kind to breathe down your neck, or demand regular updates. But I felt the terror all the same when going into his office to describe what I'd been upto. But he'd sit there with those half-closed eyes staring off into space as I spoke, and then the observations would come, carefully crafted, and enough to make me scurry off and think hard before our next meeting.

As a teacher, he was brilliant. The very first time I took a class with him, I saw this. His style of presentation, how he organized his material, and even his impeccable boardwork: these are all things I teach my students today. His lectures weren't flashy: they were solid, and profound, and in his own mellow way, he was able to convey intuition, rigor and beauty with the kind of clarity one dreams of possessing. To flip the truism about doing and teaching around, he did, and taught even better as a result of it.

I had less contact with him after graduation than I should have had. I was doing the whole 'be your own person, strike out on your own' thing. I'd bump into him occasionally at conferences, but as he got more involved in his investment efforts, he stopped attending conferences regularly (or so it seemed) and even that contact dried up. As someone just said to me in an email today morning, 'Life is fleeting'.

It's a strange feeling, to lose your advisor so suddenly like this, and to hear about it on twitter, of all things. I'm not even sure what I'm feeling, except a sense of numbness, and a feeling that something has shifted, permanently, underneath.